Lecture 8 - Learning & Memory Flashcards
Neuroplasticity?
The NS’s potential for physical or chemical change, it enhances its adaptability.
What four experiences can change the brain?
- Development.
- Culture.
- Preferences.
- Coping.
Learning is common to these experiences.
A recent definiton of learning included how many distinct rules or guidelines for what is considered learning?
137.
Learning can be defined as:
The process or acquiring new information and how to apply it to a new situatoin.
What does Hebb’s rule state about learning?
That there is a connection between two neurons that will strengthen if they are activated in the same space at the same time.
One of the functional rules that underlie learning.
Learning vs. Memory?
- Learning is a change in an organism’s behavior as a result of experience.
- Memory is the ability to store and recall or recognizze previous experience.
What are Engrams?
The basic cellular component that memories are made from.
Is operant conditioning localalized to any brain circuit?
- No.
- The encessary circuits will var with the task requirements.
What did the cat learn in Throndike’s puzzle box experiment?
Actions have consequences.
What are the categories of memory?
- Implicit memory [unconscious].
- Explicit memory [conscious].
- Emotional [unconscious & conscious].
- Declarative memory.
- Procedural memory.
Implicit vs. Explicit memory?
- Implicit memory is when subjects demonstrate knowledge, such as a skill, conditioned response, or recaling events on prompting, but cannot explicitly retreive the information.
- Explicit memory is when subjects retrieve an item and indicae that they know they retrieved the correct item.
Priming?
This is using a stimulus to sensitize the NS to a later presentation of the same or a similar stimulus.
Declarative memory?
Ability to recount what one knows, to detail the time, place, and circumstances of events.
Often lost in amnesia.
Procedural memory?
Ability to recall a movement sequence or how to perform some act or behavior.
ie. writing and typing.
Learning Set?
The implicit understanding of how a problem can be solved with a rule that can be applied in may different situations.
Does the brain process implicit and explicit memories the same way?
- No.
- Implicit information is processed in a bottom-up or data-driven manner.
- Explicit information is processed in a top-down or conceptually driven manner.
Short-term and long-term memory?
Short-term is only a few minutes, with the information being held briefly and then discarded.
Long-term is an indefinite duration, it could be help for a lifetime.
What place in the NS can be identified as the location of memory and learning?
No single place in the NS can be identified as so.
What are some terms that describe conscious memory?
- Explicit.
- Declarative.
- Fact.
- Sematic.
- Conscious recollection.
- Working.
What are some terms that describe unconscious memory?
- Implicit.
- Nondeclarative.
- Skill.
- Habit.
- Skills.
- Integration.
- Perceptual.
- Nonassociative.
Autobiographical memory?
Episodic memory for events pegged to specific place and time contexts.
What type of information is lost in sensory memory?
Unattended memory.
What type of information is lost in short-term memory?
Unrehearsed information.
What type of information is lost in long term memory?
Some information may be lost over time.
Where are autobiographical memories stored in the brain?
Key regions:
- Ventromedial prefrontal cortex [vmPFC].
- Hippocampus.
- Pathways between them ^.
Story of K.C.?
Suffered severe traumatic brain injury that produced multiple cortial lesions.
Cognitive abilities and short term memory were intact, but their episodic autobiographical amnesia covering the entire life from birth was damaged.
Who is Karl Lashley?
He searched [unsuccessfully] for the neural circuits underlying memories.
His hypothesis was that memories must be represented in the perceptual and motor circuitry used in problem solving.
He argued that movements must be performed as motor sequences, movement modules pre programmed by the brain and produced as a unit, with the next sequence held in readiness while the ongoing one is under way.
Story of H.M.?
Had a bilateral medial temporal lobe resection done.
His seizures originated in the region of the amygdala, hippocampal formation, and associated subcortical structures, and these were removed bilaterally.
After his surgery, he had severe amnesia, lacking explicit memory.
His implicit memory was left intact.
Story of J.K.?
Had impaired implicit memory with intact explicit memory.
Developed Parkinson diseases in his mid-70s and began to experience memory problems at 78.
Damage to basal ganglia as a result.
Structures that participate in certain types of explicit memory?
- Hippocampus.
- Amygdala.
- Entorhinal cortex.
- Parahippocampal cortex.
- Perirhinal cortex.
A sequential arrangement of two-way connections projects the major cortical regions into the perirhinal and parahippocampal cortices, which in turn projects to the entorhinal cortex and then to the hippocampus.
Visuospatial memory?
Using visual information to identify an object’s location in space.
Animals with hippocampal injuries have deficits in various forms of spatial memory.
Which region of the hippocampus was found to be much larger in London taxi drivers?
Posterior region.
What are the three types of spatial cells in rat and mouse hippocampus medial and entorhinal cortexes?
- Place cells.
- Head direction cells.
- Grid cells.
Which lobe(s) do all sensory systems project to?
Frontal lobes.
In general, the frontal lobe appears to participate in many forms of short term memory.
Korsakoff Syndrome & causes?
- The permanent loss of the ability to learn new information.
- Caused by the diencephalic damage from chronic alcoholism or malnutrion that produces a vitamin B1 deficiency.
Where do the sensory and motor neocortical areas connect?
To the medial temporal regions.
What role do basal forebrain structures play?
Maintaining appropriate activity leveels in other forebrain strucutures to process information.
Fill in the blank:
The prefrontal cortex is central to maintaining _ and memory for the _ of explicit events.
Temporary; recency.
What structure consolidates new memories?
The hippocampus.
Once memories move, hippocampal involvement is no longer needed.
Neural circuit for explicit memories?
[lobes and/or strucutres]
- Temproal lobe structures.
- Frontal lobe structures.
- Medial thalamus.
- Basal forebrain.
Neural circuit for implicit memories?
[lobes and/or strucutres]
- Basal ganglia.
- Ventral thalamus.
- Substantia nigra.
- Premotor cortex.
What neurotransmitter is necessary for basal ganglia circuits to function & may indirectly participate in implicit memory formation?
Dopamine.
Neural circuits for implicit memory order and flow?
Basal ganglia receive input from the entire neocortex and send projections first to the ventral thalamus and then to the premotor cortex.
For memories to be conscious, there must be?
Feedback to the cortex.
Emotional memory?
Memory for affective properties of stimuli or events.
Can be implicit or explicit.
Amygdala is critical for emotional memory.
Neural circuits for emotional memories?
The amygdala has close connections with medial temporal cortical structures and the rest of the cortex
Sends projections to:
- Brainstem structures that control autonomic responses.
- Hypothalamus.
- Periaquductal gray matter [PAG].
- Basal ganglia.
At the neural level, what is memory associated with?
Changes at the synapse.
Long Term Potentiation?
Involves persistent strengthening of synapse based on recent activity patterns (produces a long-lasting increase in signal transmission between 2 neurons).
Mechanism for creating memories.
Think of yasy example.
Long Term Depression?
Low-frequency stimulation produced a decrease in EPSP size.
Mechanism for clearing out old memories.
Sensitization?
Opposite of habituation.
Enhances the response to some stimulus [organism becomes hyperresponsive to a stimulus].
Habituation?
- Learned behavior in which the response to a stimulus weakens with repeated presentations.
- Habituation does not result from an inability of either the sensory neuron or the motor neuron to produce action potentials, both the sensory neurons and motor neuron retain this ability in response to direct electrical stimulation.
What neurotransmitter plays a key role in the neuroplasticity of LTP and LTD?
Glutamate.
What 2 receptor types does Glutamate act on in the post synaptic membrane?
- AMPA
- normally responds to gluatamate. - NMDA
- double gated channels.
- normally blocked by magnesium ions.
What two things must occur together or rapidly for NMDA receptors to open?
- Depolarization of the synaptic membrane, displacing Mg2+ from pore.
- Activation by glutamate from the presynaptic neuron.
Experience can change the brain in two ways, those are?
- Modifying existing circuitry.
- Creating novel circuitry.
What is the simplest way to find synaptic change?
To look for gross changes in the morphology of dendrites.
More dendrites = more connections.
What can existing circuits be modifed by?
- experience.
- hormones.
- drugs.
Fear conditioning is associated with?
[epigenetics]
Rapid methylation.
Epigenetic changes related to experiences may?
- contribute to the inheritance of phenotypes across generations.
Can experience alter cortical maps?
Yes.
What neurotrophic factor stimulates neurons to grow dendrites and synapses and in some cases promotes the survival of neurons?
Nerve Growth Factor [NGF].
Seven guiding principles of brain plasticity.
- Behavioral change reflects brain change.
- All nervous systems are plastic in the same general way.
- Plastic changes are age specific.
- Prenatal events can influence brain plasticity throughout life.
- Plastic changes are brain region depedent.
- Experience dependent changes interact.
- Plasticity has pros and cons.
Ways to recover from brain damage?
- The brain to form new connections to allow it to do more for less.
- ## Generate new neurons to produce new neural circuits.
